PH-dependant synthesis, structures and luminescent properties of a series of novel lanthanide phosphonate coordination polymers

Abstract

A series of two-dimensional layered lanthanide phosphonates, based on 4′-((hydroxy(methoxy)phosphoryl)methyl)-[1,1′-biphenyl]-2-carboxylic acid (H3L′ = HOOC-C6H4-C6H4-CH2-PO(OH)OCH3), Ln(HL)(H2L)(H2O) (H3L = HOOC-C6H4-C6H4-CH2-PO(OH)2), [Ln = La (1), Ce (2), Eu (3), Gd (4), Tb (5), La0.59Eu0.12Tb0.29 (6)] have been obtained by pH-dependent hydrothermal synthesis promoted by ultrasonic. Coordination polymers 1–6 are characterized by single-crystal X-ray diffraction analysis, elemental analysis, infrared spectroscopy, powder X-ray diffraction and thermogravimetry measurements. Their photoluminescence properties are investigated and found that the emission wavelength of 6 could be turned by varying the composition of Ln ions from ligand-centered blue light emission (La3+), to Ln-centered green (Tb3+) and red (Eu3+) light emission, exhibiting white light emission. The magnetic properties of 4 and 5 are also studied.